persist download mesh

core/src/main/groovy/com/muwire/core/Core.groovy

@@ -173,7 +173,7 @@ public class Core {
 		eventBus.register(SearchEvent.class, fileManager)
         
         log.info("initializing mesh manager")
-        MeshManager meshManager = new MeshManager(fileManager)
+        MeshManager meshManager = new MeshManager(fileManager, home)
         eventBus.register(SourceDiscoveredEvent.class, meshManager)
 		
 		log.info "initializing persistence service"

core/src/main/groovy/com/muwire/core/mesh/MeshManager.groovy

@@ -1,18 +1,29 @@
 package com.muwire.core.mesh
 
+import java.util.stream.Collectors
+
 import com.muwire.core.Constants
 import com.muwire.core.InfoHash
+import com.muwire.core.Persona
+import com.muwire.core.Personas
 import com.muwire.core.download.Pieces
 import com.muwire.core.download.SourceDiscoveredEvent
 import com.muwire.core.files.FileManager
 
+import groovy.json.JsonOutput
+import groovy.json.JsonSlurper
+import net.i2p.data.Base64
+
 class MeshManager {
     
     private final Map<InfoHash, Mesh> meshes = Collections.synchronizedMap(new HashMap<>())
     private final FileManager fileManager
+    private final File home
     
-    MeshManager(FileManager fileManager) {
+    MeshManager(FileManager fileManager, File home) {
         this.fileManager = fileManager
+        this.home = home
+        load()
     }
     
     Mesh get(InfoHash infoHash) {
@@ -40,4 +51,39 @@ class MeshManager {
             return
         mesh.sources.add(e.source)
     }
+    
+    private void save() {
+        File meshFile = new File(home, "mesh.json")
+        synchronized(meshes) {
+            meshFile.withPrintWriter { writer ->
+                meshes.values().each { mesh ->
+                    def json = [:]
+                    json.infoHash = Base64.encode(mesh.infoHash.getRoot())
+                    json.sources = mesh.sources.stream().map({it.toBase64()}).collect(Collectors.toList())
+                    json.nPieces = mesh.pieces.nPieces
+                    writer.println(JsonOutput.toJson(json))
+                }
+            }
+        }
+    }
+    
+    private void load() {
+        File meshFile = new File(home, "mesh.json")
+        if (!meshFile.exists())
+            return
+        JsonSlurper slurper = new JsonSlurper()
+        meshFile.eachLine { 
+            def json = slurper.parseText(it)
+            InfoHash infoHash = new InfoHash(Base64.decode(json.infoHash))
+            Pieces pieces = new Pieces(json.nPieces, Constants.DOWNLOAD_SEQUENTIAL_RATIO)
+            
+            Mesh mesh = new Mesh(infoHash, pieces)
+            json.sources.split(",").each { source -> 
+                Persona persona = new Persona(new ByteArrayInputStream(Base64.decode(source)))
+                mesh.sources.add(persona)
+            }
+            
+            meshes.put(infoHash, mesh)
+        }
+    }
 }